A Power Outage Puts 1.9 Million Maryland Water Customers on Essential Use Only

A power failure at a single water treatment plant put nearly two million people on water restrictions Tuesday. Early on September 29, one of the two electrical feeds serving WSSC Water's Potomac Water Filtration Plant in Maryland went down. The other feed had just been restored after routine maintenance by Pepco, the local electric utility. With the plant unable to run, WSSC Water asked all 1.9 million of its customers in Montgomery and Prince George's counties to use water only for essential needs starting at 8:45 a.m.

The Potomac plant matters because of its size. It normally produces 100 to 120 million gallons a day and supplies about 75 percent of the utility's service area, which borders Washington, DC. The backup Patuxent plant kept running at 90 to 95 million gallons a day, but average demand across the two counties is about 170 million gallons a day. The gap had to come out of stored water in the system's tanks, which is also the water firefighters draw from. So the utility asked for shorter showers, no lawn watering, fewer flushes, and no laundry or dishwasher loads until further notice.

The water stayed safe to drink throughout, and no boil water advisory was issued. Conserving early was the way to keep it that way, since a distribution system that loses pressure can pull in contamination. One power feed was restored by midday, and the plant resumed producing water Tuesday evening while crews brought each system back online. As of the utility's last update Tuesday night, the essential-use request still applied to every customer until production returns to normal and the system stabilizes. WSSC Water and Pepco are investigating why the second feed failed.

For a prepared household, the lesson is in the chain of events. The water did not slow because of a drought or a broken main. It slowed because the power did, and the plant's own backup could not carry the load. Utilities lean on each other, so a power outage can reach your tap, your sewer lift station, and the gas pump down the street. A home water storage reserve is the simplest hedge against that chain, and one gallon per person per day for at least three days covers a short disruption like this one. If the request had turned into a boil advisory, knowing how to purify water at home would have kept the kitchen running without a trip to a stripped store shelf.

A restriction like this is also a low-stakes rehearsal. Run through what surviving with no running water asks of you, from flushing with a bucket to washing hands from a jug, while the taps still work. The same planning that helps you prepare for a power outage covers the water side too, because in most homes the two arrive together. If your household has never tried it, a one day no water challenge on a weekend shows you exactly which habits break first.

WSSC Water expects to lift the request once the Potomac plant is back at full output, so check the utility's updates before you water the lawn or run a full load. Two counties found out this week how much of a normal day rides on one plant and one power line. Know that ahead of time, and you can stay prepared rather than scared.